Mordanting assistant and process for using the same



351 inorganic.

Patented May 30, 1933 1 UNITED STATES PATENT ol-"rlca ALAN A. cLAELIN, OF WINCHESTER, MAssAoH sETTs, AssIGNoR To NIAo E T i V CHEMICALS CGRPOR-ATION, A CORPORATION OF NEW YORK MORDANTING ASSISTANT AND rRo'oEssiEo'R USING THE SAME N Drawing.

This invention relates to mordanting textile fibers of animal origin for the purpose of fixing dyes therein and to a new assistant for mordanting operations. My invention especially concerns the use of aldol (CI-I CHOHCH CHO) as an assistant for mordanting Wool and woolen fabrics in connection with salts of chromic acid.

The application of many dyestuffs to textile fibers requires the use of a mordant. In the case of dyeing operations on wool, the mordant frequently is applied before the dyestufi' and usually takes the form of a metallic salt, such as a chromate or a dichromate, fixed in the wool fibers. Salts of chromic acid are the principal mordants which are used to any extent, but salts of other metallic elements such as aluminum, iron, tin and similar metals, that is, salts of aluminic,

.20 ferric, stannic, etc. acids as Well as of chromic acid, have been proposed for this purpose and my invention is applicable thereto in so far as their use is analogous to that of the salts of chromic acid. The dyeing of silk and other .25 animal textile fibers may closely follow, in certain instances, the methods applied to wool. I shall hereinafter describe my invention with respect to mordanting operations on Wool employing a salt of chromic acid as so the mordant, but the invention is not limited to this application.

Many substances have been employed as mordanting assistants. These were, for the most part, acidic substances both organic and Among such assistants may be listed sulphurous and sulphuric acid and their salts, oxalic, acetic, lactic and tartaric acids and various compounds of these latter substances. In the employment of acidic as- ..40; sistants with chromic salts, it is generally true that the rate at which the chromic salt is absorbed in the fibers varies directly with the acidic strength of the assistant, and that in cases where the absorption is rapid the tendency of the dye subsequently fixed on the fiber to rub off is increased. This tendency is technically known as crocking. Aldol possesses an advantage due to the fact that it causes a gradual and even deposition or 0 reduction of the mordant at a slower rate Application filed February 18. 1931.' SBriaINo. 516,846.

assistants heretofore employed. r

I may practice my'invention by treating 5 woolen fibers or fabric in a'boiling bath comprising a solution of sodium dichromate andaldol. The amount of aldol employed may Very widely according to the dye being used. In general, the quantity ranges from about one-third of the molecular proportion of sodium dichromate'which is present'to an amount slightly in excess of the molecular proportion of sodium dichromate The action of the aldol effectively fixesthe chro- 5a nnum salt, probably as acomplex hydrate, 1n the woolenfibers. The fabric may now be removed from the bath and rinsed preparae tory to being dyed. 1 r

The following example is illustrative of 9;v the invention as applied to the usualpractice of mordanting woolen fabrics: 1.

A bath is prepared which contains 3% of sodium dichromate and to this is added 3% of a 50% solution of aldol. The bath is heated to 12091 and the cloth is entered into the bath. The bath is then slowly brought to boiling temperature and boiled forfan hour. At the end of this time the cloth is removed, rinsed, and entered into the dyebath proper which is heated to 1209 F.. Thisdye bath contains 3% of Chrome blue black R (color Index No. 202) and 1.5% of gallocyanine (color Index No. 883). It is slowly brought to a boil and boiled for an hour or untilthe dyestulf is exhausted. The cloth is then, rinsed and finished in the usual manner. V In industrial practice the above procedure is frequently varied. Instead of first subjecting the; textile fibers to a mordanting bath andv then to a dyeing bath, the fibers are dyed and the mordant is then: aflixed in the same or in a separate bath. This process is termed the after-chrome or top-chrome? process. When it is used it is customary to employ about one-half as much mo-rdant as is used when the mordant is applied. first. Assists ants are not always desirable in top-chrome dyeing, their use being dependent upon the type of dye used. Ihave found that aldol is,

which comprises a substantial proportion of aldol.

'2. An assistant for mordanting animal textile fibers with salts of chromic acid which comprises a substantial proportion of aldol.

3. An assistant for mordanting animal textile fibers with alkaline metal dichromates which comprises a substantial proportion of aldol.

4. A process for mordanting wool which comprises treating the wool with a solution containing a salt of chromic acid and a substantial proportion of aldol.

5. A process for mordanting wool which comprises treating the wool with 'a'solution containing an alkaline metal dichromate and a substantial proportion of aldol.

6. A process for mordanting wool which comprises treating the wool with a solution containing sodium dichromate and a substantial proportion of aldol.

7. A process for mordanting wool which comprises entering woolen cloth into a bath containing 3% sodium dichromate and 3% of a 50% solution of ald'ol at a temperature of about 120 F., heating the bath to boiling temperature and continuing to boil the bath for a period suflicientto aflix the chrome mordant in the fibers of the cloth.

8. A process for top-chroming wool which comprises subjecting the wool to the dyeing action of a dyestufi' of the chromotrop series and then treating it with a solution containing a salt of chromic acid and a substantial proportion of aldol. v

9. Aprocess for t'op-chroining wool which comprises subjecting the wool to the dyeing action of a dyestufi of the chromotrop :series and then treating'it with a solution containing sodium dichromate and 'a substantial proportion of aldol.

10. A process for mordanting wool which comprises entering the wool into a bath contain'ing sodium dichromate and a quantity of aldol equal to from about one-third to slightly in excess of the molecular proportion of sodium dichromate in the bath, and thereafter heating the bath to boiling for a erio'd sufficient to aflix the mordant in the bers of the wool.

11. A process for mordanting wool which comprises entering woolen cloth into a bath ALAN A. CLAFLIN. 

